Abstract

The mode characteristics are demonstrated for InAlGaAs/InP circular nanolasers bonded on silicon wafer, which consist of a core height of 800 nm coated by silica/aluminum on the bottom and sidewalls. The lasing mode spectra agree well with the simulated mode spectra obtained by the 3D FDTD technique for 750 and 450 nm radius nanolasers. For the 250 nm radius nanoresonator, resonant modes with Q factors 400–790 are numerically predicted with a mode wavelength interval up to 200 nm. The mode selection related to the cavity size and location of the active region is critical for nanocavity lasers to operate over a wide temperature range. In addition, the size limit is estimated for high-Q dielectric mode in the nanoresonators. Finally, electric-injection circular nanolasers are discussed with the TE0,1,1 mode.

Figures (12)

(a) Schematic of a metallic-confined nanolaser, (b) side view SEM image of a nanoresonator with a core radius of 450 nm, and (c) top view SEM image of a nanolaser with a core radius of 450 nm after etching InP substrate.

(a) Emission spectra at 173 K and the pumping powers of 0.3, 0.6, and 1.2 mW; the inset is the lasing mode power versus the pumping power. (b) Lasing spectra at 93, 113, 133, 173, and 213 K and the pumping power of 1.2 mW, for the nanolaser with the core radius of 750 nm under continuous-wave optical pumping. The spectra for 173, 133, 113, and 93 K have been offset from zero on the y axis by 0.15, 0.3, 0.45, and 0.6, respectively.

Field distributions of (a)–(e) Hz and (f) Ez in the nanoresonator with the radius of 750 nm at (upper) y=0 and (lower) z=0 or other z values as stated, for (a) TE7,1,1, (b) TE1,4,1, (c) TE0,3,2 at z=−250nm, (d) TE3,2,3 at z=−375nm, (e) TE4,2,2 at z=150nm, and (f) TM7,1,1.

(a) Lasing spectra at 83, 123, and 163 K and the pump power of 1.2 mW, the inset is the lasing mode output versus the pumping power; and (b) lasing spectra at the pump powers of 0.3, 0.6, and 1.2 mW and 123 K for the nanolaser with the core radius of 450 nm. The lasing peaks are fitted by two resonant modes at the pumping power of 0.3 and 0.6 mW.

(a) Resonant mode spectra of the nanoresonators with the radius R=430, 450, and 470 nm, and (b) photoluminescence spectra of the laser wafer at 113, 213, and 293 K and the resonant spectra calculated from Hz and Ez for the nanoresonator with the radius of 450 nm.

Field distributions Hz of the nanoresonator with the radius of 450 nm at (upper) y=0 plane and (lower) z=−250nm plane or stated again, for (a) TE0,2,2, (b) TE2,2,2, (c) TE0,2,1 at z=0, (d) TE1,2,2, and (e) TE4,1,1 at z=0, respectively.

Field distributions Hz of the nanoresonator with the radius of 250 nm and tilted angle of 8° at (upper) y=0 plane and (lower) z=0 plane or stated again, for (a) TE0,1,3, (b) TE1,2,1, (c) TE0,1,2 at z=−250nm, respectively.

Field distributions Hz of the nanoresonator with the radius of 250 nm and tilted angle of 0° at (upper) y=0 plane and (lower) z=0 plane or stated again, for (a) TE1,2,1, (b) TE0,1,3, (c) TE0,1,2 at z=−250nm, respectively.

(a) Mode Q factors and (b) wavelengths versus the radius for TE0,1,3, TE0,1,2, and TE0,1,1 in the nanoresonators. The dashed and dotted lines are the size limit estimated by perfect confinement for dielectric mode in the nanoresonators with circular and square cross sections.

Field distributions of TE0,1,1 mode in the nanoresonator with the core radius of 200 nm at (upper) y=0 plane and (lower) z=0 plane for (a) magnetic field Hz, and (b) electric field intensity |E|2, respectively.